Waterproof watchcase with moisture indicator



E. PIQUEREZ 3,052,083

WATERPROOF WATCHCASE WITH MOISTURE INDICATOR Sept. 4, 1962 Filed Dec. 20, 1954 United States Patent 3,052,083 WATERPROOF WATCHCASE WITH MOISTURE INDHCATOR Ervin Piquerez, Bassecourt, Bern, Switzerland Filed Dec. 20, 1954, Ser. No. 476,448 Claims priority, application Switzerland Dec. 22, 1953 1 Claim. (Cl. 58-88) This invention relates to a watchcase construction and more particularly to a watchcase construction incorporating waterproof features.

According to the main or principal object of this invention, the watchcase of the above construction contains a substance the color of which varies according to humidity content inside the case whereby the fluidtightness of said case may be readily checked.

A further object is to prevent any small quantity of water penetrating the watchcase from acting upon the gearing or any other part of the movement, before the watch has been controlled and restored to its original Waterproof condition. To this purpose the substance used is meant to absorb completely a small quantity of water.

With these and other objects not specifically mentioned, in view, the invention consists in certain combinations and arrangement of parts, which will be hereinafter described and specifically pointed out in the claim.

Referring to the drawing which forms a part of the specification, FIG. 1 is a face view of a wrist watchease the inside of which is assumed to be dry;

FIG. 2 is the same view as FIG. 1, after a leakage has occurred;

FIGS. 3 and 4 are views similar to the preceding ones, but covering a second embodiment of the invention;

FIGS. 5 and 6 are respectively a side section and a face of a third embodiment, FIG. 5 being a cross-section through line VV of FIG. 6;

FIGS. 7 and 8 are views similar to FIGS. 5 and 6, but covering a fourth embodiment, FIG. 7 being a crosssection through line VIIVII of FIG. 8.

FIGS. 1 and 2 illustrate a watchcase 1 with a cardboard disc 2 fixed to the bottom. A substance changing color with the moisture content of the air is applied to the central part 2a of the disc and a substance which does not change color in the presence of moisture is applied to the annular part 2b of the disc. The color of the disc surface is uniform as shown in FIG. 1 when the air inside the watchcase is dry. If the air gets moist the central part 2a becomes darker and the change in color is easily noticeable because of the contrast with the annular zone 2b of the disc, the color of which has not varied the moisture. Thus the disc 2 allows checking the watertightness of the case.

In the second embodiment of the invention, as per FIGS. 3 and 4, a disc 4 is applied to the dial plate 3 of the movement. The same substances are respectively applied to the central part 4a and the annular part 4b of the disc as above to 2a and 2b respectively, and the color, when the watchcase is dry, is the same on 4a as on the periphery 4b. Again the substance in the central part 4a of the disc gets darker when the air in the watchcase is moist and the substance in annular part 4b does not change color.

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Evidently it is also possible to apply the substances directly onto the dial plate, the color being uniform when the air is dry. In FIGS. 5 and 6 the watch comprises a glass cap 5 and a tablet 6, made of porous porcelain impregnated with chloride of cobalt. The tablet is set in a metallic ring 7 which is fixed with glue or by pressing to the inner central face of the glass cap.

It is a matter of experience that when a waterproof watchcase construction has a leakfor instance after a long stay in waterthe water that has got through accumulates in the joints of the case. The latter is warmed by coming into contact with the skin or lying in the sun, and the water changes into steam that settles in the shape of droplets under the central section of the glass cap because glass not being such a good conductor of heat as metal is, remains colder for a longer time. On the other hand the central part of the glass cap is that where the substances can most easily be seen Without interfering with the reading of time since it covers only the central part of the hands. When an appropriate color changing substance is used, this can also absorb completely a small quantity of moisture entering the case; thus allowing a checking of the watertightness of the watch before water starts acting upon the gearing or any other part inside the case. The embodiment illustrated in FIGS. 7 and 8, differs from FIGS. 5 and 6, only in the fixing of the tablet 8, without the help of a ring, to a supporting frame 9, possibly made of a transparent synthetic material such as that sold under the registered trademark Plexiglas. The frame 9 extends diametrically across the dial underneath the glass cap and is rigidly secured at each end to the periphery of said cap. The frame may also be secured to the inner side of the glass cap to the case body or to the dial plate.

What I claim is:

In a waterproof watch comprising a case, a movement located in the case, a dial plate secured to said case and a glass cap fluidtightly fitted to the case over the dial plate at a small distance therefrom, the combination of a support extending diametrically across the underside of the glass cap and rigidly secured at each end to the periphery of said cap, a moisture detecting layer of a substance the color of which changes in contact with any moisture entering the space between the cap and the dial plate, said layer being carried by said support on the side facing the glass cap to be visible through the latter.

References Cited in the file of this patent UNITED STATES PATENTS 1,826,115 Ziebarth Oct. 6, 1931 2,446,361 Clibbon Aug. 3, 1948 2,609,655 Vermot Sept. 9, 1952 2,621,468 Colomb Dec. 16, 1952 FOREIGN PATENTS 10,565 Switzerland July 12, 1895 284,120 Great Britain Jan. 26, 1928 393,094 Great Britain June 1, 1933 215,706 Switzerland Oct. 16, 1941 247,044 Switzerland Nov. 1, 1947 58,753 France Nov. 25, 1953 

